1. Field of the Invention
This invention relates primarily to furnaces and in particular to heat exchangers for use in furnaces.
2. Description of the Background Art
In one form of conventional domestic furnace, air to be heated is passed in heat transfer association with a serpentine heat exchanger. The heat exchanger defines a flow path for hot products of combustion conventionally produced by combustion of fluid fuel, such as fuel oil, gas, etc.
The hot products of combustion, in passing through the heat exchanger, transfer their heat to the air to be heated, conventionally referred to as the room air, and are then exhausted through a suitable flue.
It is desirable, in such furnaces, to maximize the amount of heat transfer from the products of combustion to the room air. Thus, it is conventional to utilize a serpentine heat exchanger for effecting a continuingly increasing temperature of the room air as it flows from an inlet portion of the heat exchanger zone to an outlet portion thereof.
It is further conventional, in the use of such heat exchangers, to heat the room air by a counterflow of the hot products of combustion through the heat exchanger, In certain installations, it is most desirable to effect a uniform distribution of the heat transfer while accepting a somewhat lower overall efficiency therein.